1. Field of the Invention
The present invention relates to an image shooting device with a camera shake correction function, a camera shake correction method and a storage medium recording a pre-process program for camera shake correction process, and more particularly to a image shooting device with a camera shake correction function, a camera shake correction method and a storage medium recording a pre-process program for camera shake correction process which are capable of avoiding the degradation of an image by correcting its camera shake.
2. Description of the Related Art
When taking a picture using digital camera (image shooting device) built in a cellular phone or the like, for example, the vibration of a hand carrying the cellular phone during an exposure time affects an image to be taken in. In order to suppress this influence of the hand vibration, camera shake correction is applied to the taken image.
Recently, digital cameras, more particularly digital cameras mounted on cellular phones have been spread with remarkable speed. Requirements for the performance and serviceability of a digital camera by users have also increased.
In response to such requirements, as to the performance, high pixels and the high zoom magnification have remarkably progressed and as to the serviceability, small size and light weight have remarkably progressed.
However, the improvement of these performance/serviceability in turn has easily caused a blur due to such camera shake. More particularly, in the case of a digital camera mounted on a cellular phone, since it is always carried, for example, pictures are often taken in a very dark place. However, no flash is often mounted. Therefore, in this case, a blur due to camera shake is easy to occur compared with other digital cameras.
As method for coping with the camera shake, an optical image correction method and an image correction method by a digital process have been proposed.
In general digital cameras, the optical image correction method is already commercialized, and in digital cameras mounted on cellular phones, the commercialization of the image correction method by the digital process has just started.
As other camera shake correction methods, for example, the methods disclosed by Patent references 1 and 2 are known.
Patent reference 1 discloses a technology of automatically improving shutter speed and sensitivity (a gain value) by n times, shooting images for n frames at one time and obtaining image data whose camera shake is corrected on the basis of n pieces of image data obtained by the series of imaging.
Patent reference 2 discloses a technology of shooting a plurality of images in an exposure time shorter than a camera shake limit exposure time if the calculated appropriate exposure time is expected to be longer than the camera shake limit exposure time.
Patent reference 3 discloses an image processing device for correcting the camera shake of an image shot by an image shooting device. This image processing device comprises a consecutive image shooting unit for consecutively shooting an object in prescribed time intervals and obtaining a plurality of images, a camera shake detection unit for detecting camera shake information about the camera shake of the image shooting device according to the timing of the consecutive image shooting and a camera shake correction unit for correcting the camera shake of at least one of a plurality of images shot by the consecutive image shooting unit on the basis of the camera shake information corresponding to each image detected by the camera shake detection unit and the plurality of images. Thus, the image shooting device can shoot scenes intended by a photographer while correcting its camera shake with high accuracy in high speed.
In the electronic camera with consecutive image shooting function disclosed by Patent reference 4, camera shake information indicating the detection result of camera shake state at the time of consecutive image shooting from an angular velocity sensor is stored in RAM and also when the file of consecutive image data obtained at the time of consecutive image shooting is recorded on a memory card, the camera shake information is attached and recorded. When reproducing the consecutive images recorded on the memory card, camera shake correction is performed on the basis of the attached camera shake information. Thus, an electronic camera with a camera shake correction function to maintain high image quality can be provided with no complex structure.
Patent reference 1: Japanese patent Publication No. 2004-266648“Camera Shake Correction Apparatus and Camera Shake Correction Program”
Patent reference 2: Japanese patent Publication No. 2004-279514 “Camera Shake Compensation Device”
Patent reference 3: Japanese patent Publication No. 2002-247444 “Image Processor and Recording Medium For Recording Image Processing Program”
Patent reference 4: Japanese patent Publication No. 2000-299813 “Electronic Image Pickup Device”